Metallic globules

Ammonium chloride is used as a flux ia the melting furnace because the large surface of the cathodes favors the formation of dross, ie, oxide-coated globules of ziac. The dross is separated by Hquation or air-swept milling iato metal and oxide fractions. In the latter, the oxide fraction is swept out of the mill and can be returned to roasting for the elimination of chloride. Metallic ziac is recycled. Overall melting efficiency is 96—98%. 

Phosphides. Zirconium forms several phosphides ZrP [39318-19-9] 2 [ 12037-80-8] and ZrP g [12066-61 -4]-, they are part of the Zr—P phase diagram (137). The solubiUty of phosphoms in zirconium metal is low, ca 50 ppm, and at higher concentrations it collects as separate globules at the metal grain boundaries. Analysis indicates that this material is Zr P. 

The spectacular success (in 1807) of Humphry Davy, then aged 29 y, in isolating metallic potassium by electrolysis of molten caustic potash (KOH) is too well known to need repeating in detail." Globules of molten sodium were similarly prepared by him a few days later from molten caustic soda. Earlier experiments with aqueous solutions had been unsuccessful because of the great reactivity of these new elements. The names chosen by Davy reflect the sources of the elements. 

Spatter globules of metal expelled during welding onto the surface of parent metal or of a weld. 

Fluxing is much more difficult with aluminium than with tin and zinc. The oxide layer on molten aluminium, though thin, is most tenacious. Any article leaving the bath is liable to be contaminated with streaks of this oxide or with globules of metal entangled in the oxide him. 

Charles Hall was inspired by his chemistry professor at Oberlin College, who observed that whoever perfected an inexpensive way of producing aluminum would become rich and famous. After his graduation. Hall set to work in his home laboratory, trying to electrolyze various compounds of aluminum. He was aided by his sister Julia, who had studied chemistry and shared Charles interests. Julia helped to prepare chemicals and witnessed many of the electrolysis experiments. After only eight months of work. Hall had successfully produced globules of the metal. Meanwhile, Heroult was developing the identical process in France. 

The enzymes are protein molecules having globular structure, as a rule. The molecular masses of the different enzymes have values between ten thousands and hundred thousands. The enzyme s active site, which, as a rule, consists of a nonproteinic organic compound containing metal ions of variable valency (iron, copper, molybdenum, etc.) is linked to the protein globule by covalent or hydrogen bonds. The catalytic action of the enzymes is due to electron transfer from these ions to the substrate. The protein part of the enzyme secures a suitable disposition of the substrate relative to the active site and is responsible for the high selectivity of catalytic action. 

Note that this method enables one to observe variation of electric conductivity of a sample due to adsorption of hydrogen atoms appearing as a result of the spillover effect, no more. In a S3rstem based on this effect it is rather difficult to estimate the flux intensity of active particles between the two phases (an activator and a carrier). The intensity value obtained from such an experiment is always somewhat lower due to the interference of two opposite processes in such a sample, namely, birth of active particles on an activator and their recombination. When using such a complicated system as a semiconductor sensor of molecular hydrogen (in the case under consideration), one should properly choose both the carrier and the activator, and take care of optimal coverage of the carrier surface with metal globules and effect of their size [36]. 

In order to develop more informative and direct method of studying the spillover effect of active particles, the authors of [37] suggested to use the sensor method of detecting migrating particles based on separation of sensor and emitter (donor) of active particles. The latter consists of small metal globules, or clusters (with a diameter of about 20-30 A) of Pt, Pd, Ni, etc. (activator) deposited on quartz or sapphire (AI2O3) plate in the form of a strip less than 1 cm wide. The sensor for detection of hydrogen atoms consisted of a zinc oxide strip (with a width of about 0.1 cm and thickness wlOO nm) deposited on the same plate at a distance of 0.03 or 0.6 cm (two versions) from the inner boundaries of activator strips [38]. 

Any unreacted metal is easily viable as a globule, floating on the surface of the darker liquid. A flashlight aids in rapid inspection. 

Heavy sdvery-white liquid does not wet glass forms tiny globules the only metal that occurs at ordinary temperatures as a hquid and one of the two hquid elements at ambient temperatures (the other one being bromine) density 13.534 g/cm3 solidifies at -38.83°C vaporizes at 356.73°C vapor pressure 0.015 torr at 50°C, 0.278 torr at 100°C and 17.29 torr at 200°C critical temperature 1,477°C critical pressure 732 atm critical volume 43cm3/mol resistivity 95.8x10 ohm/cm at 20°C surface tension 485.5 dynes/cm at 25°C vis-... 

Under these circumstances [said Davy] a vivid action was soon observed to take place. The potash began to fuse at both its points of electrization. There was a violent effervescence at the upper surface at the lower, or negative, surface, there was no liberation of elastic fluid but small globules having a high metallic lustre, and being precisely similar in visible characters to quicksilver, appeared, some of which burnt with explosion and bright flame, as soon as they were formed, and others remained, and were merely tarnished, and finally covered by a white film which formed on their surfaces. 

The little metallic globules always appeared at the cathode, and these had an astonishing way of bursting into flame when thrown into water. They skimmed about excitedly with a hissing sound, and soon burned with a lovely lavender light Davy found that the new metal... 

One method he finally adopted was to mix the non-conducting, dry earth (lime, strontia, or baryta) with excess potash and fuse it. When he covered the alkaline mixture with naphtha and passed an electric current through it, he soon saw metallic globules rising and bursting into flame, but when the flame died out, there remained nothing except potash and the alkaline earth with which he had started (2,3). 

In experimental studies, metal-sulfide liquids form rounded globules that will sink through a silicate matrix that is itself partly molten (e.g. Walker and Agee, 1988). The density difference is sufficient that segregation of a metallic core though a mush of liquid and crystals should be rapid. However, sinking of metallic liquid through a solid or mostly... 

Two types of metallic globules were observed in the waste form. These were principally elemental molybdenum with trace elements in solution and elemental palladium with other trace elements in solution. In the case of molybdenum, the silicon... 

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